May 8, 2014: In this photo provided by Yemen's Defense Ministry, Yemen's army soldiers hold up their weapons at an area seized from Al Qaeda in the southeastern province of Shabwa, Yemen. (AP Photo/Yemen's Defense Ministry) (The Associated Press)

In this photo provided by Yemen's Defense Ministry, Yemeni army vehicles take position on the frontline of fighting with al-Qaida in the southeastern province of Shabwa, Yemen, Thursday, May 8, 2014. Yemeni armed forces on Thursday swept al-Qaida fighters out of a district in the country's south, one of the main goals of the major offensive waged by the military the past two weeks, the Defense Ministry said, amid fears of retaliatory attacks which officials say prompted the closure of the US embassy in the capital as a precaution. (AP Photo/Yemen's Defense Ministry) (The Associated Press)

SANAA, Yemen – A suspected U.S. drone strike in southern Yemen killed six Al Qaeda militants on Monday, military and security officials said.

The drone hit a car with Al Qaeda fighters in Marib province, in the Husoun al-Jalal area in Abieda Valley, said the officials, speaking on condition of anonymity in line with regulations. They said authorities were checking for the identities of the slain militants.

Last year and in early January, drone strikes killed more than 12 suspected Al Qaeda militants in the same area of Marib province.

The U.S. considers Yemen's branch of Al Qaeda, also known as Al Qaeda in the Arabian Peninsula, to be the most dangerous in the world. The group overran large swaths of territory in southern Yemen in 2011 but the military has pushed back and over the past few weeks, the army and security forces have stepped up an offensive to rout militants from their strongholds.

The U.S., which trains Yemen's counterterrorism forces, has been waging a heavy campaign of drone strikes in the impoverished country against suspected Al Qaeda targets, launching more than 100 such strikes since 2002, according to the nonpartisan public policy institute New America Foundation.

However, civilian casualties in the drone strikes have sparked anger in the country and among human rights groups.

Yemen's Interior Ministry corrected late Sunday an earlier press release saying three suspected Al Qaeda militants were killed in clashes with security forces not far from the presidential palace in the capital, Sanaa, during the day. The new statement said the three victims were civilians who died in the crossfire.

Meanwhile, Yemen's Defense Ministry said two Al Qaeda militants were killed and one was wounded in Sunday's clashes with government troops in Hadramawt and Shabwa provinces.

The statement identified the slain militants as Abu Mohammed al-Hadrami, who was killed in Hadramawt, and Yahia Baruwais, killed in Shabwa. It said Al Qaeda fighter Said Bawazeer, also known as Abu Fatima, was wounded in Hadramawt

Outside Yemen, the country's Al Qaeda branch is blamed for a number of unsuccessful bomb plots aimed at Americans, including an attempt to bring down a U.S.-bound airliner with explosives hidden in the bomber's underwear and a second plot to send mail bombs hidden in the toner cartridges on planes headed to the U.S.